Roos, aged 23, first came to Evans’ attention before he signed for Derby County 12 months ago.

“He caught my eye when he was playing for Nuneaton,” he said. “You could see then what a talent the boy was. People may say he played only five games for Derby last season but had he played more times at senior level then he probably wouldn’t be signing for Rotherham United.”

The 6ft 5in shot-stopper could have gone to Bolton Wanderers for £25,000, when Dougie Freedman, was in charge before Derby snapped him up, and staff at the Macron Stadium have since admitted the club made a huge mistake in not signing him.

Evans says he had narrowed down his keeper search to Roos and last season’s Millers loan star, Emi Martinez, of Arsenal, and had decided he would take whoever he could get first.

Kelle Roos with Millers No 2 Paul Raynor

“We had many talks with Derby and Arsenal,” he said. “Eventually we got the green light from Derby. I’m delighted Kelle has joined us. He has got everything except a number of matches under his belt.”

The Millers boss draws a parallel between the Dutchman and Martinez, who became a key man last term after arriving from the Emirates Stadium with only a handful of Gunners games and a loan spell with Sheffield Wednesday to his name.

“Even though Martinez had played in the Champions League for Arsenal before he joined us last season, I don’t think there were many people out there who knew much about him,” he said.

Rotherham play the first game of the trip north of the border tomorrow against Greenock Morton and Evans revealed he could have a full squad to choose from as players recover from pre-season niggles.

Meanwhile, the club have cancelled the contract of Conor Newton by mutual consent and the midfielder has signed for League Two Cambridge United.